Crude fiber digestion apparatus



Nov. 19, 1940. NEWMAN ET AL 2,222,463

CRUDE FIBER DIGESTION APPARATUS Filed July 13, 1939 fizueman's 9 a; 0.57am; m M W/&,;. MAJ A4 far/26545.

Patented Nov. 19, 1940 UNITED STATES PATENT OFFICE CRUDE. FIBER DIGESTION APPARATUS Application July 13, 1939, Serial No. 284,309

7 Claims.

The invention relates to improvements in crude fiber digestion apparatus of the reflux condenser type. Apparatus of this type is commonly used in determining the crude fiber content of such materials as bread or other baked products, grain and stock feeds, macaroni, milk, chocolate, nuts, plants, prepared mustard, roasted coffee, spices,

tea and wheat flour. In the course of such a crude fiber determination test a sample of the material being tested is boiled in a digestion flask with first a solution of acid and then a solution of an alkali. After various other treatments the residue of the sample is weighed and the crude fiber content determined by comparison with the original sample weight. For complete details of the process reference may be made to the outline of official tests for the purpose contained in Official and Tentative Methods of Analysis of the Association of Official Agricultural Chemists (1935) pages 340-341. For the present it is sufficient to note that since the test is a quantitive one it is of utmost importance that there should be no loss of liquid or vapor from the digester if accurate results are to be obtained.

Generally stated, it is an object of the invention to provide a reflux condenser digestion apparatus which is easy to manipulate, is efiectually sealed against loss of liquid or vapor, and in which frothing of the boiling solution is minimized.

Another object is to provide an apparatus of the type indicated embodying a beaker with a condenser removab-ly positioned in its top, and in which the condenser is constructed and arranged in a novel manner so as to cause the condensate flowing from it to wash down the beaker side walls and thereby minimize frothing, and also arranged in such manner as to form an effectual vapor seal at the beaker mouth, and to keep the top of the beaker cool enough to handle.

Still another object is to provide such an apparatus embodying a novel cooling water supply arrangement for the condenser such that the beaker and condenser can readily be handled as a freely movable unit in agitating the beaker contents to inhibit frothing of the solution.

Further objects and advantages of the invention will become apparent as the following description proceeds, taken in connection with the accompanying drawing in which:

Figure l is a general perspective view of a crude fiber digestion apparatus embodying the invention.

Fig. 2 is an enlarged vertical sectional view of one of the beaker-condenser units included in the apparatus of Fig. 1.

For purposes of exemplification the invention has been shown herein as embodied in a digestion apparatus particularly suited for use in making crude fiber determination tests of various materials. Even though a particular embodiment of the invention has been shown and described in some detail there is no intention to thereby limit the invention to such an embodiment but, on the other hand, the appended claims are intended to cover all modifications and alternative constructions falling within the spirit and scope of the invention.

The illustrative digester (Fig. 1) includes among its principal elements a series of glass beakers In, each provided with an individual heating unit II and a water cooled reflux condenser l2 fashioned to plug the top of the associated beaker. The heating units H are of the electrical resistor type, being mounted on a suitable base l3. Within this base are housed individual control rheostats (not shown) manipulated by knobs M for accurately controlling the energization of the corresponding heater units.

The beaker condenser units It, I2 are all identical and, accordingly, a description of one will suffice for all. The beaker Ill (Fig. 2) is of conventional cup shaped form with cylindrical side walls terminating in a slightly outwardly flaring lip l5 at the beaker mouth. The usual pouring spout l (Fig. l) is provided at the mouth of the beaker. The beaker is preferably of large diameter as compared to its height so so as to expose a large area of liquid of minimum depth, to the heating unit.

The condenser l2 (Fig. 2) embodies nested inner and outer sheet metal shells ll and I8 arranged with their side and bottom walls in spaced relation and having their marginal edges seamed together at 19 to define a cooling water chamber. Preferably, both of the shells |'ll8 are made of pure nickel. The inner shell I! is fashioned in the form of a deep dome overlying substantially the entire cross sectional area of the interior of the beaker H3. The outer shell I8 is fashioned in the form of a cylindrical cup shaped housing dimensioned to fit snugly within the beaker mouth, and an annular bead 2| on the housing rests on the beaker lip 15. This bead 2| is located at a sufficient distance above the lower edge of the condenser assembly so that the condenser will project down into the mouth of the beaker a substantial distance and below the root of the spout l6.

To cool the condenser dome l'l cooling water is supplied to the Water jacket chamber 20 through an inlet tube 22 This tube extends from the top wall of the housing It to a point adjacent the bottom of the chamber 20 and at which point the entering cooling water is discharged. By thus leading the entering cooling water to the bottom of the chamber 20 adequate cooling of the upper portion of the beaker walls is insured. After the cooling water circulates through the water jacket chamber 20 it is discharged through an outlet tube 22, also located in'the wall of the housing I8.

Cooling water is supplied for all of the condensers l2 (Fig. 1) through a horizontal supply pipe 23 overlying the base i3 a substantial distance above the latter. This pipe 23 is supported by a riser pipe 24 fixed to the base 43 and through which water is supplied to it. A valve 25 serves to control the rate of flow of cooling water. Sim-- ilarly, all of the condensers l2 are arranged to discharge into a common waste pipe 26, fixed to the supply pipe 23 by clamps 27, and communicating with a suitable drain (not shown) through an outlet pipe 28. Communication between the condenser inlets 22 and outlets 22 and the respective supply and waste pipes 23 and 26 is afforded by individual flexible hose connections 29 and 36, respectively.

during boiling of the solution.

placed in the beaker Ill. The condenser unit i2 is then inserted in the top of they beaker and the associated heater I I energized a selected amount determined by the setting of its rheostat. Furthermore, cooling water is supplied to the condenser cooling chamber 20 as heretofore de- In the operation of the apparatus described a solution 3| (Fig. 2) of material to be treated is scribed. The solution 3! is thus boiled and vapors rising from the surface of the liquid impinge against the water cooled dome I! where they are condensed and from which they drain back into the body of liquidin the bottom of the beaker. This operation is, of course, continued until the digestion is complete.

By utilizing the deep dome H in the condenser, which terminates at its lower edges at the side walls of the beaker, the condensate formed on the surface of the dome is caused largely to drain down the side walls of the beaker. In this way the beaker side walls are continually washed down and frothing is minimized. Furthermore, it will be noted that the entering cooling water is discharged into the lower part of the water jacket chamber 26 so that the lower portion of the condenser housing i8 is maintained at quite a low temperature. As a result any vapor which tends to penetrate upward between the telescopically fitting surfaces of the housing 18 and the beaker ii! is condensed, thereby forming an effectual vapor seal. As was heretofore noted, the cool lower portion .of the condenser inserted into the beaker mouth also serves to cool the upper portion of the beaker side walls so that it can readily be grasped by the user at this point without danger of burning his fingers. In general, therefore, it will be seen that a digestion apparatus has been provided in which frothing is minimized and in which any loss of vapor or liquid is eifectually prevented so that extremely accurate test resultsmay be obtained.

We claim as our invention:

1. In a digesting apparatus the combination of a beaker having an open top, a reflux condenser fashioned to plug the top of said beaker, and said condenser including two nested generally cup shaped inverted inner and outer sheet metal shells arranged with their side walls in spaced relation to define a cooling Water chamber between them and dimensioned to telescope down into the beaker with portions thereof defining said chamber located in directly contacting heat exchange relation with the upper portion of the beaker walls so that vapor tending to penetrate between the telescoped beaker and condenser walls will be cooled and condensed by the latter to form a liquid seal against the escape of vapor between such telescoped walls.

2. In a digesting apparatus, the combination of a cup shaped beaker having a cylindrical side wall terminating in a round open top, a deep metal dome dimensioned to overlie substantially the entire top of said beaker, a housing fixed to said dome and defining a water jacket chamber about the exterior of said dome, and means for removably supporting said dome and housing assembly on the top of said beaker with the peripheral edge of said dome substantially against the inner side wall of said beaker so that liquid condensed on the cooled surface of the dome will drain down the beaker side wall to wash it down and thereby minimize frothing of a solution being boiled in the beaker.

3. In a digesting apparatus, the combination of a generally cup shaped beaker presenting a round open top, a condenser assembly of plug like form removably inserted in the top of said beaker, said assembly including inner and outer sheet metal shells, the outer shell being of inverted cup shape and the inner shell in the form of a deep dome nested within the outer shell and secured I to it at its marginal edges, the side and bottom walls of the shells being spaced apart to define a cooling water chamber between them, and said outer shell having a projection on an intermediate outer portion of its side wall arranged to engage the top of the beaker and locate the condenser assembly with said cooling water chamber extending down into the beaker a substantial distance in directly contacting intimate heat exchange relation with the beaker side wall.

4. 'In a digesting apparatus, the combination of a generally cup shaped beaker presenting a round open top, a condenser assembly of plug like form removably inserted in the top of said beaker, said assembly including inner and outer sheet metal shells, the outer shell being of inverted cup shape and the inner shell in the form of a deep dome nested within the outer shell and secured to it at its marginal edges, the side and bottom walls let arranged to discharge into the lower portion of said chamber.

5. A digestion apparatus of the character described comprising, in combination, a series of horizontally alined heating units presenting generally flat top surfaces, individual cup shaped beakers removably seated on corresponding ones of the heating units and movable freely both laterally and vertically therefrom, generally plug shaped reflux condenser units removably fitted on the tops of said beakers, each of said condensers having a cooling water inlet and outlet, a cooling water supply pipe and a waste pipe extending horizontally over the heating units in spaced relation above them, and flexible hose connections between each of said inlets and said supply pipe and between each of said outlets and said waste pipe to permit free lateral and vertical movement of the beakers when the latter are oiT of the heating units and without removing the condensers from the beakers.

6. A digestion apparatus of the character described comprising, in combination, a base having a series of horizontally alined heating units thereon, individual cup shaped beakers removably supported above corresponding ones of the heating units, generally plug shaped reflux condenser units removably fitted on the tops of said beakers, each of said condensers having a cooling water inlet and outlet, a cooling'water supply pipe and a waste pipe extending horizontally over the heating units in spaced relation above them, means including a riser pipe connected to said supply pipe and fixed to said base for supporting said supply pipe, means for clamping said waste pipe to said supply pipe to support the same, and flexible hose connections between each of said inlets and said supply pipe and between each of said outlets and said Waste pipe, said hose connections depending from said pipes to support the condensers attached thereto substantially above the corresponding heater units.

'7. A digestion apparatus of the character described comprising, in combination, a row of heater units, cup-shaped open-"mouthed beakers removably seated on said heater units, a reflux condenser removably plugged in the open mouth of each of said beakers, said condensers embodying water cooled exterior walls telescoped within and directly contacting the beaker side walls to form a liquid seal therefor by the condensation of any vapor tending to penetrate therebetween, each of said condensers having a cooling water inlet and outlet, cooling Water waste and supply pipes rigidly positioned above the row of heating units, and flexible hose connections from said pipes to said inlets and outlets of suflicient length to hang limply when the condensers are plugged in the beakers so as not to tend to pull out the condensers and thus break the seals but also short enough to suspend the condensers above the heating units when the condensers are removed from the beakers.

ALEXANDER I. NEWMAN.

LOYAL C. SHORT. 

